As computer usage in the workplace becomes ever more pervasive, efficient network administration becomes an increasingly complex task. In an office environment, individual computer terminals are typically networked to a server over a local area network (LAN) such as an Ethernet LAN. In a LAN, each computer communicates with the network through a LAN controller. Typically, the LAN controller is housed on a network interface card (NIC), sometimes called a LAN card or Ethernet card. However, recently, the LAN controllers are being integrated directly into computer motherboards. Each LAN controller is represented as a node on the LAN by a unique identification number. A server computer also connected to the LAN acts as the gateway to outside networks and as centralized data storage. From the administrator's end, LAN implementations allow administrative tasks such as software installation, virus scanning, file management, network email service, data backups, etc., to be performed over the network from a single central location. Through use of access levels, the network administrator may manage all the other computers or nodes on the network from his or her computer. From the user end, LAN implementations allow access to the Internet, shared file storage space and access to shared networked output devices, such as printers.
Due in part to the dynamic technology dependent nature of today's workplace, network administrators must constantly perform functions requiring access of individual network nodes from the administrator's computer. These functions can include configuring new nodes, updating and installing software, adding network printers, scanning for viruses, and file back-ups, to name a few. Typically, many of these administrative functions are scheduled for execution after normal business hours so as to minimize interference with user applications during the work day. However, during these after hour times, individual computers on the LAN may be in one of a variety of power conserving modes, also known as sleep modes. Typically, the power conserving modes cause the display to be put in a low power state, the hard drive to be spun down and even the microprocessor to reduce its clock frequency or to be shut down completely. Having the computers powered down can make it difficult if not impossible to schedule and implement after hours network events. If the administrator has to physically turn on each machine, at least some of the efficiencies of centralized network administration are lost.
This problem of needing to wake-up computers over the LAN led to the invention of a protocol known as MAGIC PACKET technology. MAGIC PACKET technology is a proprietary hardware solution incorporated into the card or board-based Ethernet controller for waking up a PC over the LAN developed and owned by Advanced Micro Devices, Inc. of Sunnyvale, Calif. Before entering a powered down or sleep mode, the LAN controller is put into a MAGIC PACKET mode. In this mode, the device will no longer generate any network transmits, but will monitor all incoming frames to determine if any of them is a MAGIC PACKET frame. The LAN controller will scan all incoming frames addressed to the node for a specific data sequence, which indicates to the controller that this is a MAGIC PACKET frame. A MAGIC PACKET frame must meet the general requirements for the specific LAN technology employed, such as SOURCE ADDRESS, DESTINATION ADDRESS and CRC. Also in the frame is the MAGIC PACKET, which is a specific sequence consisting of 16 duplications of the IP address of the specific node. The sequence can be located anywhere within the packet, but must be preceded by a synchronization stream. The synchronization stream allows the scanning state machine to be much simpler by identifying the location of the sequence.
If the address matching circuit determines that the MAGIC PACKET for that node has arrived, the MAGIC PACKET mode is disabled and full power is restored to the system allowing the network administrator to perform data backups, software installations, etc. Alternatively, full power may be restored by conventional means such as depressing a key on the keyboard or moving/clicking the mouse. After the desired operation has been performed, or after a sufficient time period has expired, a command signal may be sent the node over the LAN to return the node to the power saving MAGIC PACKET MODE. Because the LAN controller already has built-in address matching circuitry in order to recognize regular frames addressed to the node, implementation of MAGIC PACKET technology is simplified. For a full description of MAGIC PACKET technology refer to U.S. Pat. No. 6,049,885 hereby incorporated by reference in its entirety.
Due in part to advances in liquid crystal displays and battery technology as well as reductions in disk drive and circuit board size, demand for laptop, palmtop and other wireless computer devices has grown significantly. The typical LAN is no longer comprised only of desktop computers physically tethered to the network. Instead, today's office environment consists of a mixture of wired and wireless computer devices which often have their own internal wireless cards. Also, in order to avoid the expense of retrofitting office space with network communication cables, wireless network cards are even being used with stationary desktop-type computers. As a result, the need arose to extend the functionality of LAN access to wireless devices. To accommodate this need, a standard for wireless LAN, known as IEEE 802.11x was created. Using one or more wireless access points (APs), distributed throughout an office space, wireless devices are able to seamlessly connect to the LAN in a manner identical to and at speeds comparable to tethered workstations over short distances. Each wireless device has a wireless network interface card with a transceiver that facilitates two way communication with the AP. The AP has a service set identifier (SSID) which is a 32 character identifier attached to the header of packets sent over the wireless LAN (WLAN). The SSID differentiates one WLAN from another. All access points and all devices attempting to connect to a specific WLAN must use the same SSID. Each node on the WLAN has a unique hardware destination address that uniquely identifies that node.
The presence of wireless device nodes on the LAN complicates the implementation of wake-up over the LAN. Firstly, wireless devices are not always plugged into a permanent power source. Usually, these devices are capable of running off line power or their own internal batteries. Secondly, wireless devices access the LAN by communicating with a specific access point. Thus, in order for the network administrator to send a message to a particular node, he must know the SSID of the access point that the wireless device communicates with. However, because of the portable nature of wireless devices, the administrator may not know the location of the each device within the premises, and thus, the access point with which each device will communicate. As a result, it becomes difficult to address a wake-up signal to specific devices knowing only the destination address of each device.
The description herein of various advantages and disadvantages associated with known apparatus, methods, and materials is not intended to limit the scope of the invention to their exclusion. Indeed, various embodiments of the invention may include one or more of the known apparatus, methods, and materials without suffering from their disadvantages.